This invention relates to a field marker for a sprayer boom of the type which is supported on the end of the sprayer boom and mechanically acts upon the ground or crop to form a line which can subsequently be followed in a further passage of the sprayer boom.
One problem which such mechanical markers have to encounter is the fact that they have to act at various times of the year on bare ground and on the ground when covered with crop of various types.
Particularly when used with crop, it is necessary for the marker to provide a visible line while not seriously damaging the crop to avoid losses which could become considerable if spraying is repeated on the same crop.